Orally administered drugs are provided to the patient in many dosage forms, including solid forms such as capsules, caplets or tablets and liquid forms such as solutions, emulsions or suspensions. Pharmaceuticals administered in solid form are usually intended to be swallowed whole. Often the disagreeable taste of a drug does not need to be considered in formulating swallowable tablets or capsules. Because these dosage forms are in the mouth such a short time the pharmaceutical's taste can easily be masked with an exterior coating on the tablet.
Children, older persons, and many other persons including disabled or incapacitated patients often have trouble swallowing tablets or capsules. In these situations, it is desirable to provide the drug either in a chewable solid form or a liquid form. For many patients, including pediatric and geriatric patients, a liquid oral dosage form is, preferable to a chewable dosage form. A liquid dosage is preferable for this class of patients because of the ease with which it may be swallowed. Additionally, patients may be more inclined to comply with their medication instruction if the dosages are easier to ingest.
However, a common problem associated with liquid pharmaceutical dosage forms is the often disagreeable taste of a drug that may manifest itself when the drug is in a liquid dosage form. Sometimes, the taste of the drug in the dosage form may be overpowered by adding sweeteners or flavoring agents to the liquid dosage. These agents mask the bitter or unpleasant taste of drugs. However, these agents are not totally effective in concealing the unpalatable taste of pharmaceuticals.
Liquid suspension dosage forms also have stability problems associated with maintaining the drugs in suspension. Poorly formulated liquid pharmaceutical suspensions allow the drug to settle out as a sediment, thereby reducing the therapeutic concentration of drug in the suspension. This results in under dosing or over dosing of the patient, which may seriously compromise the patient's recovery.
Additionally the pharmaceutical suspension should be readily pourable so that the dosage is easy to administer. The requirement that a pharmaceutical suspension is readily pourable effectively places an upper limit on the viscosity of the suspension. This limitation also indirectly limits the amount of pharmaceutical actives that the suspension will suspend.
In view of these difficulties it would be desirable to develop a ready-to-use pharmaceutical suspension with a high degree of stability and good taste masking characteristics. Therefore, there exists a need for a suspension system for pharmaceutical actives that minimizes sedimentation of the active ingredients and provides a pleasant tasting liquid dosage.
The present invention discloses a stable aqueous suspension system for pharmaceutical actives, which can be combined with sweeteners and flavoring agents to provide a palatable liquid dosage form. This dosage form is also physicochemically stable and especially well suited for both geriatric and pediatric applications.